Prosthetic valve for transluminal delivery

ABSTRACT

A prosthetic valve assembly for use in replacing a deficient native valve comprises a replacement valve supported on an expandable valve support. The valve support, which entirely supports the valve annulus, valve leaflets, and valve commissure points, is configured to be collapsible for transluminal delivery and expandable contact the anatomical annulus of the native valve when the assembly is properly positioned. Portions of the valve support may expand to a preset diameter to maintain coaptivity of the replacement valve and to prevent occlusion of the coronary ostia.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. Ser. No.10/412,634 filed on Apr. 10, 2003, which is (1) a continuation-in-partof U.S. Ser. No. 10/130,355 filed on May 17, 2002, which is the U.S.national phase under §371 of International Application No.PCT/FR00/03176, filed on Nov. 15, 2000, which was published in alanguage other than English and which claimed priority from FrenchApplication No. 99/14462 filed on Nov. 17, 1999, now French Patent No.2,800,984, and (2) also a continuation-in-part of InternationalApplication No. PCT/FR01/03258 filed on Oct. 19, 2001, which waspublished in a language other than English and which claimed priorityfrom French Application No. 00/14028 filed on Oct. 31, 2000, now FrenchPatent No. 2,815,844.

FIELD OF THE INVENTION

The present invention relates to a prosthetic cardiac valve and relateddeployment system that can be delivered percutaneously through thevasculature, and a method for delivering same.

BACKGROUND OF THE INVENTION

Currently, the replacement of a deficient cardiac valve is oftenperformed by opening the thorax, placing the patient underextracorporeal circulation or peripheral aorto-venous heart assistance,temporarily stopping the heart, surgically opening the heart, excisingthe deficient valve, and then implanting a prosthetic valve in itsplace. U.S. Pat. No. 4,106,129 to Carpentier describes a bioprostheticheart valve with compliant orifice ring for surgical implantation. Thisprocedure generally requires prolonged patient hospitalization, as wellas extensive and often painful recovery. It also presents advancedcomplexities and significant costs.

To address the risks associated with open heart implantation, devicesand methods for replacing a cardiac valve by a less invasive means havebeen contemplated. For example, French Patent Application No. 99 14462illustrates a technique and a device for the ablation of a deficientheart valve by percutaneous route, with a peripheral valvular approach.International Application (PCT) Nos. WO 93/01768 and WO 97/28807, aswell as U.S. Pat. No. 5,814,097 to Sterman et al., U.S. Pat. No.5,370,685 to Stevens, and U.S. Pat. No. 5,545,214 to Stevens illustratetechniques that are not very invasive as well as instruments forimplementation of these techniques.

U.S. Pat. No. 3,671,979 to Moulopoulos and U.S. Pat. No. 4,056,854 toBoretos describe a catheter-mounted artificial heart valve forimplantation in close proximity to a defective heart valve. Both ofthese prostheses are temporary in nature and require continuedconnection to the catheter for subsequent repositioning or removal ofthe valve prosthesis, or for subsequent valve activation.

With regard to the positioning of a replacement heart valve, attachingthis valve on a support with a structure in the form of a wire ornetwork of wires, currently called a stent, has been proposed. Thisstent support can be contracted radially in such a way that it can beintroduced into the body of the patient percutaneously by means of acatheter, and it can be deployed so as to be radially expanded once itis positioned at the desired target site. U.S. Pat. No. 3,657,744 toErsek discloses a cylindrical, stent-supported, tri-leaflet, tissue,heart valve that can be delivered through a portion of the vasculatureusing an elongate tool. The stent is mounted onto the expansion toolprior to delivery to the target location where the stent and valve areexpanded into place. More recently, U.S. Pat. No. 5,411,552 to Andersenalso illustrates a technique of this type. In the Andersen patent, astent-supported tissue valve is deliverable percutaneously to the nativeheart valve site for deployment using a balloon or other expandingdevice. Efforts have been made to develop a stent-supported valve thatis self-expandable, using memory materials such as Nitinol.

The stent-supported systems designed for the positioning of a heartvalve introduce uncertainties of varying degree with regard tominimizing migration from the target valve site. A cardiac valve that isnot adequately anchored in place to resist the forces of the constantlychanging vessel wall diameter, and turbulent blood flow therethrough,may dislodge itself, or otherwise become ineffective. In particular, theknown stents do not appear to be suited to sites in which the cardiacwall widens on either proximally and/or distally of the valve annulussitus. Furthermore, the native cardiac ring remaining after ablation ofthe native valve can hinder the positioning of these stents. These knownsystems also in certain cases create problems related to the sealingquality of the replacement valve. In effect, the existing cardiac ringcan have a surface that is to varying degrees irregular and calcified,which not only lessens the quality of the support of the stent againstthis ring but also acts as the source of leaks between the valve andthis ring. Also, these systems can no longer be moved at all afterdeployment of the support, even if their position is not optimal.Furthermore, inflating a balloon on a stented valve as described byAndersen may traumatize the valve, especially if the valve is made froma fragile material as a living or former living tissue.

Also, the existing techniques are however considered not completelysatisfactory and capable of being improved. In particular, some of thesetechniques have the problem of involving in any case putting the patientunder extracorporeal circulation or peripheral aorto-venous heartassistance and temporary stopping of the heart; they are difficult toput into practice; they do not allow precise control of the diameteraccording to which the natural valve is cut, in view of the latercalibration of the prosthetic valve; they lead to risks of diffusion ofnatural valve fragments, often calcified, into the organism, which canlead to an embolism, as well as to risks of perforation of the aortic orcardiac wall; they moreover induce risks of acute reflux of blood duringablation of the natural valve and risk of obstruction of blood flowduring implantation of the device with a balloon expandable stent forexample.

SUMMARY OF THE INVENTION

The object of the present invention is to transluminally provide aprosthetic valve assembly that includes features for preventingsubstantial migration of the prosthetic valve assembly once delivered toa desired location within a body. The present invention aims to remedythese significant problems. Another objective of the invention is toprovide a support at the time of positioning of the replacement valvethat makes it possible to eliminate the problem caused by the nativevalve sheets, which are naturally calcified, thickened and indurated, orby the residues of the valve sheets after valve resection. Yet anotherobjective of the invention is to provide a support making possiblecomplete sealing of the replacement valve, even in case of an existingcardiac ring which has a surface which is to varying degrees irregularand/or to varying degrees calcified. Another objective of the inventionis to have a device that can adapt itself to the local anatomy (i.e.varying diameters of the ring, the subannular zone, the sino-tubularjunction) and maintain a known diameter of the valve prosthesis tooptimize function and durability. The invention also has the objectiveof providing a support whose position can be adapted and/or corrected ifnecessary at the time of implantation.

The present invention is a prosthesis comprising a tissue valvesupported on a self-expandable stent in the form of a wire or aplurality of wires that can be contracted radially in order to makepossible the introduction of the support-valve assembly into the body ofthe patient by means of a catheter, and which can be deployed in orderto allow this structure to engage the wall of the site where the valveis to be deployed. In one embodiment, the valve is supported entirelywithin a central, self-expandable, band. The prosthetic valve assemblyalso includes proximal and distal anchors. In one embodiment, theanchors comprise discrete self-expandable bands connected to the centralband so that the entire assembly expands in unison into place to conformmore naturally to the anatomy.

The valve can be made from a biological material, such as an animal orhuman valve or tissue, or from a synthetic material, such as a polymer,and includes an annulus, leaflets and commissure points. The valve isattached to the valve support band with, for example, a suture. Thesuture can be a biologically compatible thread, plastic, metal oradhesive, such as cyanoacrylate. In one embodiment, the valve supportband is made from a single wire bent in a zigzag manner to form acylinder. Alternatively, the valve support band can be made from aplurality of wires interwoven with one another. The wire can be madefrom stainless steel, silver, tantalum, gold, titanium, or any suitabletissue or biologically compatible plastic, such as ePTFE or Teflon. Thevalve support band may have a loop at its ends so that the valve supportband can be attached to an upper anchor band at its upper end, and alower anchor band at its lower end. The link can be made from, forexample, stainless steel, silver, tantalum, gold, titanium, any suitableplastic material, or suture.

The prosthetic valve assembly is compressible about its center axis suchthat its diameter can be decreased from an expanded position to acompressed position. The prosthetic valve assembly may be loaded onto acatheter in its compressed position, and so held in place. Once loadedonto the catheter and secured in the compressed position, the prostheticvalve assembly can be transluminally delivered to a desired locationwithin a body, such as a deficient valve within the heart. Once properlypositioned within the body, the catheter can be manipulated to releasethe prosthetic valve assembly and permit it to into its expandedposition. In one embodiment, the catheter includes adjustment hooks suchthat the prosthetic valve assembly may be partially released andexpanded within the body and moved or otherwise adjusted to a finaldesired location. At the final desired location, the prosthetic valveassembly may be totally released from the catheter and expanded to itsfully expanded position. Once the prosthetic valve assembly is fullyreleased from the catheter and expanded, the catheter may be removedfrom the body.

Other embodiments are contemplated. In one such alternative embodiment,this structure comprises an axial valve support portion that has astructure in the form of a wire or in the form of a network of wiressuitable for receiving the replacement valve mounted on it, and suitablefor supporting the cardiac ring remaining after the removal of thedeficient native valve. The embodiment may further comprise at least oneaxial wedging portion, that has a structure in the form of a wire or inthe form of a network of wires that is distinct from the structure ofsaid axial valve support portion, and of which at least a part has, whendeployed a diameter greater or smaller than that of said deployed axialvalve support portion, such that this axial wedging portion or anchor issuitable for supporting the wall bordering said existing cardiac ring.The embodiment preferably further comprises at least one wire forconnecting the two portions, the wire or wires being connected at pointsto these portions in such a way as not to obstruct the deployment ofsaid axial portions according to their respective diameters. Theembodiment thus provides a support in the form of at least two axialportions that are individualized with respect to one another with regardto their structure, and that are connected in a localized manner by atleast one wire; where this wire or these wires do not obstruct thevariable deployment of the axial portion with the valve and of the axialwedging portion(s) or anchors. The anchors may be positioned distally orproximally.

The presence of a structure in the form of a wire or in the form of anetwork of wires in the axial valve support portion makes possible aperfect assembly of this valve with this structure, and the shape aswell as the diameter of this axial portion can be adapted for supportingthe existing cardiac ring under the best conditions. In particular, thisaxial valve support portion can have a radial force of expansion suchthat it pushes back (“impacts”) the valve sheets that are naturallycalcified or the residues of the valve sheets after valve resection ontoor into the underlying tissues, so that these elements do not constitutea hindrance to the positioning of the replacement valve and also allowfor a greater orifice area. This structure also makes it possible tosupport an optional anchoring means and/or optional sealing means forsealing the space between the existing cardiac ring and the replacementvalve, as indicated below.

The configuration of each anchor portion can be adapted for supportingthe cardiac wall situated at the approach to the existing cardiac ringunder the best conditions. In particular, this anchor portion can have atubular shape with a constant diameter greater than that of the axialvalve support portion, or the form of a truncated cone whose diameterincreases with distance from the axial valve support portion. Byattaching at least one anchor portion to the axial valve supportportion, the prosthetic valve assembly assumes a non-cylindrical ortoroidal configuration. This non-cylindrical configuration provides anincreased radial expansion force and increased diameter at both ends ofthe prosthetic valve assembly that may tighten the fit between the valveassembly and surrounding tissue structures. The tighter fit from anon-cylindrical configuration can favorably increase the anchoring andsealing characteristics of the prosthesis. The axial valve supportportion itself may be non-cylindrical as well.

Preferably, the tubular support has an axial valve support portion inthe form of at least two parts, of which at least one is suitable forsupporting the valve and of which at least another is suitable forpushing back the native valve sheets or the residues of the native valvesheets after valve resection, into or onto the adjacent tissue in orderto make this region able to receive the tubular support. This axialvalve support portion eliminates the problem generated by these valve orcardiac ring elements at the time of positioning of the replacementvalve. The radial force of this axial valve support portion, byimpacting all or part of the valvular tissue or in the wall or itsvicinity in effect ensures a more regular surface more capable ofreceiving the valve support axis. It also ensures a better connectionwith the wall while reducing the risk of peri-prosthetic leakage.Furthermore, such a structure permits the valve to maintain a diameterwithin a preset range to ensure substantial coaptivity and avoidsignificant leakage.

The particular method of maintaining the valve diameter within a presetrange described above relates to the general concept of controlling theexpanded diameter of the prosthesis. The diameter attained by a portionof the prosthesis is a function of the radial inward forces and theradial expansion forces acting upon that portion of the prosthesis. Aportion of the prosthesis will reach its final diameter when the net sumof these forces is equal to zero. Thus, controlling the diameter of theprosthesis can be addressed by addressing the radial expansion force,the radial inward forces, or a combination of both. Changes to theradial expansion force generally occur in a diameter-dependent mannerand can occur extrinsically or intrinsically. Resisting furtherexpansion can occur extrinsically by using structural restraints thatoppose the intrinsic radial expansion force of the prosthesis, orintrinsically by changing the expansion force so that it does not expandbeyond a preset diameter. The first way, referred to previously, relatesto controlling expansion extrinsically to a preset diameter to ensurecoaptivity. In one embodiment configured to control diameter, a maximumdiameter of at least a portion of the support structure may be ensuredby a radial restraint provided along at least a portion of circumferenceof the support structure. The radial restraint may comprise a wire,thread or cuff engaging the support structure. The restraint may beattached to the support structure by knots, sutures or adhesives, or maybe integrally formed with the support structure. The radial restraintsmay also be integrally formed with the support structure during themanufacturing of the support structure. The configuration of the radialrestraint would depend upon the restraining forces necessary and theparticular stent structure used for the prosthesis. A radial restraintcomprising a mechanical stop system is also contemplated. A mechanicalstop system uses the inverse relationship between the circumference ofthe support structure and the length of the support structure. As thesupport structure radially expands, the longitudinal length of thesupport structure will generally contract or compress as the wires ofthe support structure having a generally longitudinal orientation changeto a circumferential orientation during radial expansion. By limitingthe distance by which the support structure can compress in alongitudinal direction, or the angle to which the support structurewires reorient, radial expansion in turn can be limited to a maximumdiameter. The radial restraint may comprise a plurality of protrusionson the support structure where the protrusions abut or form a mechanicalstop against another portion of the support structure when the supportstructure is expanded to the desired diameter.

In an embodiment configured to control the expanded diameterintrinsically for a portion of the support, the radial expansion forceof the valve support may be configured to apply up to a preset diameter.This can be achieved by the use of the shape memory effect of certainmetal alloys like nickel titanium or Nitinol. When Nitinol material isexposed to body heat, it will expand from a compressed diameter to itsoriginal diameter. As the Nitinol prosthesis expands, it will exert aradial expansion force that decreases as the prosthesis expands closerto its original diameter, reaching a zero radial expansion force whenits original diameter is reached. Thus, use of a shape memory alloy suchas Nitinol is one way to provide an intrinsic radial restraint. Anon-shape memory material that is elastically deformed duringcompression will also exhibit diameter-related expansion forces whenallowed to return to its original shape.

Although both shape memory and non-shape memory based material mayprovide diameter-dependent expansion forces that reach zero uponattaining their original shapes, the degree of force exerted can befurther modified by altering the thickness of the wire or structure usedto configure the support or prosthesis. The prosthesis may be configuredwith thicker wires to provide a greater expansion force to resist, forexample, greater radial inward forces located at the native valve site,but the greater expansion force will still reduce to zero upon theprosthesis attaining its preset diameter. Changes to the wire thicknessneed not occur uniformly throughout a support or a prosthesis. Wirethickness can vary between different circumferences of a support orprosthesis, or between straight portions and bends of the wirestructure.

The other way of controlling diameter previously mentioned is to alteror resist the radial inward or recoil forces acting upon the support orprosthesis. Recoil forces refer to any radially inward force acting uponthe valve assembly that prevents the valve support from maintaining adesired expanded diameter. Recoil forces include but are not limited toradially inward forces exerted by the surrounding tissue and forcescaused by elastic deformation of the valve support. Opposing or reducingrecoil forces help to ensure deployment of the support structure to thedesired diameter.

Means for substantially minimizing recoil are also contemplated. Suchmeans may include a feature, such as a mechanical stop, integral withthe support structure to limit recoil. By forming an interference fitbetween the mechanical stop and another portion of the support structurewhen the support structure is expanded to its preset diameter, thesupport structure can resist collapse to a smaller diameter and resistfurther expansion beyond the preset diameter. The interference fit maycomprise an intercalating teeth configuration or a latch mechanism.Alternatively, a separate stent may be applied to the lumen of thecardiac ring to further push aside the native valve leaflets or valveremnants by plastically deforming a portion of the prosthesis. Thisseparate stent may be placed in addition to the support structure andmay overlap at least a portion of the support structure. By overlappinga portion of the support structure, the separate stent can reduce anyrecoil force acting on the support structure. It is also contemplatedthat this separate stent might be applied to the native lumen before theintroduction of the valve prosthesis described herein. Anotheralternative is to plastically deform the valve assembly diameter beyondits yield point so that the prosthesis does not return to its previousdiameter.

At portions of the prosthesis where the control of the expansion forceagainst surrounding tissue is desired, the various methods forcontrolling diameter can be adapted to provide the desired control ofexpansion force. Portions of the prosthesis may include areas used foranchoring and sealing such as the axial wedging portions previouslydescribed.

Specifically, in order to support the valve, the axial valve supportportion can have a part in the form of an undulating wire withlarge-amplitude undulations, and a part in the form of an undulatingwire with small-amplitude undulations, adjacent to said part with largeamplitude undulations, having a relatively greater radial force in orderto make it possible to push said valvular tissue against or into thewall of the passage. Preferably, the support according to one embodimentof the present invention has two axial wedging portions, one connectedto an axial end of said valve support portion and the other to the otheraxial end of this same valve support portion. These two axial wedgingportions thus make it possible to wedge the support on both sides of theexisting cardiac ring, and consequently make possible complete wedgingof the support in two opposite directions with respect to the treatedsite. If necessary, for example, in the case in which the passage withthe valve has an aneurysm, the support according to the invention has:an axial holding portion, suitable for supporting in the deployed statethe wall of the passage, and connecting wires such as the aforementionedconnecting wires, connecting said axial valve support portion and saidaxial holding portion, these wires having a length such that the axialholding portion is situated after implantation a distance away from theaxial valve support portion. This distance allows said axial holdingportion to rest against a region of the wall of the passage not relatedto a possible defect which may be present at the approach to the valve,particularly an aneurysm. The length of the connecting wires can also becalculated in order to prevent the axial holding portion from cominginto contact with the ostia of the coronary arteries. The aforementionedaxial portions (valve support, wedging, holding portions) can have astructure in the form of an undulating wire, in zigzag form, orpreferably a structure in diamond-shaped mesh form, the mesh parts beingjuxtaposed in the direction of the circumference of these portions. Thislast structure allows a suitable radial force making it possible toensure complete resting of said portions against the wall that receivesthem.

As previously mentioned, the support according to the invention can beproduced from a metal that can be plastically deformed. The instrumentfor positioning of the support then includes a balloon which has anaxial portion with a predetermined diameter, adapted for realizing thedeployment of said axial valve support portion, and at least one axialportion shaped so as to have, in the inflated state, a greater crosssection than that of the passage to be treated, in such a way as toproduce the expansion of the axial wedging portion placed on it untilthis axial wedging portion encounters the wall which it is intended toengage. The support according to this embodiment of the presentinvention can also be produced from a material that can be elasticallydeformed or even a material with shape memory, such as Nitinol, whichcan be contracted radially at a temperature different from that of thebody of the patient and which regains its original shape when itstemperature approaches or reaches that of the body of the patient.

Alternatively, the support may be made from a shape memory material thatcan be plastically deformed, or may be partially made from a shapememory material and partially made from a material that can beplastically deformed. With this embodiment, the support can be brought,by shape memory or plastic deformation, from a state of contraction to astable intermediate state of deployment between the state of contractionand the state of total deployment, and then by plastic deformation orshape memory respectively, from said intermediate state of deployment tosaid state of total deployment. In said intermediate state ofdeployment, the support is preferably configured such that it remainsmobile with respect to the site to be treated. The support may thus bebrought to the site to be treated and then deployed to its intermediatestate; its position can then possibly be adapted and/or corrected, andthen the support be brought to its state of total deployment. Oneexample of a shape memory material that can be plastically deformed maybe a nickel-titanium alloy of the type called “martensitic Nitinol” thatcan undergo plastic deformation by means of a balloon. By using aballoon to expand and stress the alloy beyond its yield point, plasticdeformation can occur. Plastic deformation by a balloon of a portion ofthe prosthesis that has already undergone self-expansion can also beused to compensate for any recoil that occurs.

Advantageously, the support according to the invention has someanchoring means suitable for insertion into the wall of the site to betreated, and is shaped in such a way as to be mobile between an inactiveposition, in which it does not obstruct the introduction of the supportinto the body of the patient, and an active position, in which it isinserted into the wall of the site to be treated. Substantially completeimmobilization of the support at the site is thus obtained. Inparticular, this anchoring means can be in the form of needles and canbe mounted on the support between retracted positions and radiallyprojected positions. Advantageously, the axial valve support portionhas, at the site of its exterior surface, a sealing means shaped in sucha way as to absorb the surface irregularities that might exist at ornear the existing cardiac ring. This sealing means can consist of aperipheral shell made from a compressible material such as polyester ortissue identical to the valve or a peripheral shell delimiting a chamberand having a radially expandable structure, this chamber being capableof receiving an inflating fluid suitable for solidifying after apredetermined delay following the introduction into said chamber. Thissealing means can also include a material that can be applied betweenthe existing cardiac ring and the axial valve support portion, thismaterial being capable of solidifying after a predetermined delayfollowing this application. Specifically, in this case, this material iscapable of heat activation, for example, by means of a laser, throughthe balloon, or capable of activation by emission of light ofpredetermined frequency, for example, by means of an ultraviolet laser,through the balloon. Said sealing means can also be present in the formof an inflatable insert with a spool-shaped cross section in theinflated state, which can be inserted between the existing cardiac ringand the axial valve support portion, Said spool shape allows this insertto conform to the best extent possible to the adjacent irregularstructures and to provide a better seal.

In one embodiment of the invention, a drug-eluting component iscontemplated. This component comprises a surface coating or matrixbonding to at least a portion of support structure. Drug elution is wellknown to those in the art. Potential drugs may include but are notlimited to antibiotics, cellular anti-proliferative andanti-thrombogenic drugs.

An assembly and method for removing the native valve is alsocontemplated. In particular, the invention has the objective ofproviding a device that gives complete satisfaction with regard to theexeresis and replacement of the valve, while allowing one to operatewithout opening of the thorax, stopping of the heart and/or opening ofthe heart, and preventing any diffusion into the circulatory system offragments of the removed valve. In one embodiment, the assemblycomprises: (a) an elongated support element; (b) a first set ofelongated blades arranged around the circumference of said elongatedelement and connected in a pivoting manner to the elongated element atthe site of their proximal longitudinal ends, each blade having a sharpedge at the site of its distal longitudinal end and configured to pivotwith respect to the elongated element between a folded up (retracted)position, in which they are near the wall of the elongated element insuch a way that they do not stand in the way of the introduction andsliding of the device in the body channel in which the valve is located,in particular in the aorta, and an opened out (protracted) position, inwhich these blades are spread out in the form of a corolla in such a waythat their sharp edges are placed in extension of one another and thusconstitute a sharp circular edge; (c) a second set of blades arrangedconsecutively to said first series of blades in the distal direction;the blades of this second set have a structure identical to that of theblades of said first set, wherein the blades of this second series areconnected to the elongated element by their distal longitudinal ends andwherein each has a sharp edge at the site of its proximal longitudinalend; (d) means making it possible to bring the blades of said first andsecond set from their retracted position to their protracted position;(e) means for permitting axial movement of the sets of blades axiallyrelative to one another between a spaced position in which one set ofblades can be placed axially on one side of the natural valve while theother set of blades is placed axially on the other side of this valve,and a proximate position in which the sharp circular edges of the twosets of blades may be brought into mutual contact for excising thenatural valve.

A method of using this assembly comprises the steps of introducing theassembly percutaneously into said body channel and delivering theassembly to a position where the first and second sets of blades arespaced on opposite sides of the natural valve using the means ofidentification. The method may further comprise putting in place asystem of peripheral aorto-venous heart assistance, extracorporealcirculation or a blood pump through the center of the delivery systemfor pumping blood, in the case of an aortic valve replacement, from theleft ventricle (proximal to the aortic valve) to the aorta (distal tothe aortic valve) in order to facilitate the flow of the blood, for thepurpose of preventing stagnation of the blood in the heart. Oneembodiment of a blood flow pump is described further below. After theassembly is positioned in place, the method further comprises spreadingthe blades of the two sets of blades out; then bringing the two setscloser together to excise the valve. The configuration of these bladesmakes it possible to execute this cutting in a single operation,minimizing the generation of fragments that can be diffused into thecirculatory system. This configuration moreover makes possible precisecontrol of the diameter according to which the natural valve is cut, inview of later calibration of the prosthetic valve. The blades may thenbe retracted for placement of the prosthetic valve.

The prosthetic valve may be deployed discretely from the assembly, inwhich case the method may comprise removing the assembly and thenseparately deploying the prosthetic valve. Preferably however, theassembly comprises a proximal prosthetic valve having an expandablesupport structure that may occupy a contracted position near the wall ofsaid elongated element for transmission through the body channel, and anexpanded position to replace the natural cardiac valve.

After excising the natural valve, the method further comprises slidingthe assembly axially in the distal direction in order to bring theprosthetic valve to the desired site in the channel, and then expandingthe prosthetic valve support into place. The assembly may then bewithdrawn, recovering the excised natural valve.

Preferably, the elongated support element is a tubular catheterpermitting blood to flow through it during the excision of the naturalvalve. The cross section of the channel of this catheter can besufficient to allow the blood to flow through this channel with orwithout the help of a pump. Continued blood flow during the excisionprocedure may limit or eliminate the need for placing the patient underextracorporeal circulation or peripheral aorto-venous heart assistance.The catheter has a lateral distal opening in order to allow the blood torejoin the body channel, for example the ascending aorta, this openingbeing arranged in such a way that the length of catheter passed throughthe blood is as short as possible. Alternatively, the catheter may havea small diameter to facilitate the introduction and delivery of theassembly in the body channel, but a small diameter might require theprovision of peripheral circulation by an external assistance systemsuch as an extracorporeal circulation system or-peripheral aorto-venousheart assistance.

Preferably, the assembly for excising the native valve includes a distalinflatable balloon, placed at the site of the exterior surface of saidelongated element; wherein the balloon is configured so as to occupy adeflated position, in which it has a cross section such that it does notstand hinder introduction and advancement of the assembly within thebody channel, and an expanded position. The balloon may be inflatedafter the positioning of the sets of blades on both sides of the naturalvalve in order to prevent reflux of the blood during the ablation of thenatural valve. If the elongated element is a catheter, this balloonmoreover makes it possible to cause blood to flow only through thecatheter. Once the prosthetic valve is positioned, the balloon isdeflated to re-establish the blood flow through the body channel.

The assembly for excising the native valve may optionally include adistal filter made of flexible material placed on the exterior surfaceof the elongated element. The filter is configured so that it can occupya retracted position or a contracted position. This filter serves tocapture possible fragments generated by the excision of the naturalvalve, for removal from the blood circulation. The assembly may includemeans for moving the sets of blades in the axial direction relative tothe balloon and/or from said filter.

The balloon and optional filter may be separate from the assembly, beingmounted on an elongated support element specific to them. In case ofoperation on a mitral valve, this balloon or filter may be introducedinto the aorta by a peripheral artery route, and the assembly is itselfintroduced into the heart by the peripheral venous system, up to theright atrium and then into the left atrium through the interatrialseptum, up to the site of the mitral valve. The prosthetic valve canadvantageously have a frame made of a material with a shape memory,particularly a nickel-titanium alloy known as “Nitinol.” This same valvecan have valve leaflets made of biological material (preserved animal orhuman valves) or synthetic material such as a polymer. When replacing anaortic valve the assembly may be alternatively introduced in aretrograde manner through a peripheral artery (femoral artery) orthrough a venous approach and transseptally (antegrade).

One embodiment of a system for deploying a prosthetic valve may comprisea blood pump insertable into the lumen of a catheter to facilitate bloodflow across the native valve and implantation sites during theimplantation procedure. When the catheter is positioned across theimplantation site, a proximal opening of the delivery catheter is on oneside of the implantation site and the lateral distal opening is onanother side of the implantation site. By inserting the blood pump intothe catheter lumen between the proximal and lateral distal openings,blood flow across the native valve and implantation sites is maintainedduring the procedure. One embodiment of the blood pump comprises arotating impeller attached to a reversible motor by a shaft. When theimpeller is rotated, blood flow can be created in either direction alongthe longitudinal axis of the catheter between the proximal and lateraldistal openings to provide blood flow across the implantation site. Thepump may be used during the native valve excision step if so carriedout.

In one application of the present invention, the prosthetic valve may beimplanted by first passing a guidewire inserted peripherally, forinstance, through a vein access; transseptally from the right atrium tothe left atrium and then snaring the distal end of the guidewire andexternalizing the distal end out of the body through the arterialcirculation. This placement of the guidewire provides access to theimplantation site from both venous and arterial routes. By providingvenous access to the native valve, massive valvular regurgitation duringthe implantation procedure may be avoided by first implanting thereplacement valve and then radially pushing aside the native valveleaflets through the venous access route.

The above embodiments and methods of use are explained in more detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of one embodiment of an assemblyof the present invention for removing and replacing a native heart valvepercutaneously;

FIG. 2 is a cross-section axial view of the assembly of FIG. 1 taken atline II-II, shown in a closed condition;

FIG. 3 is a cross-section axial view of the assembly of FIG. 1 taken atline II-II, shown in an opened condition;

FIG. 4 is a perspective schematic view of one embodiment of a prostheticvalve of the present invention;

FIGS. 5 to 9 are schematic views of the assembly of the presentinvention positioned in a heart, at the site of the valve that is to betreated, during the various successive operations by means of which thisvalve is cut out and the prosthetic valve shown in FIG. 4 deployed;

FIG. 10 is a schematic view of the prosthetic valve shown of FIG. 4shown in a deployed state;

FIG. 11 is a schematic view of an alternative embodiment of the assemblyof the present invention shown treating a mitral valve;

FIG. 12 is a cross-sectional view of a section of a blade used inexcising the native valve.

FIG. 13 is a schematic view of one embodiment of the support structureof the prosthesis assembly of the present invention;

FIG. 14 is a cross-sectional view of the support of FIG. 13 showing aheart valve supported by the central portion of the support;

FIG. 15 is an end view of the support of FIGS. 13 and 14 in the deployedstate;

FIG. 16 is an end view of the support of FIGS. 13 and 14 in thecontracted state;

FIG. 17 is a schematic view of a heart with an embodiment of the presentinventive prosthesis shown deployed in place;

FIG. 18 is a schematic view of an alternative embodiment of the presentinvention;

FIG. 19 is schematic view of an alternative embodiment of the presentinvention;

FIG. 20 is a detail view of a part of the support structure of oneembodiment of the present invention;

FIG. 21 is a schematic view of the support of FIG. 19 shown in adeployed state;

FIG. 22 is schematic view of an alternative embodiment of the presentinvention;

FIG. 23 is a detail view of the support of FIG. 22 shown in thecontracted state;

FIG. 24 is a detail view of the support of FIG. 23 taken along line23-23;

FIG. 25 is a detail view of the support of FIG. 22 shown in the expandedstate;

FIG. 26 is a detail view of the support of FIG. 25 taken along line25-25;

FIG. 27 is a schematic view of an alternative embodiment of the presentinvention;

FIG. 28 is a detailed cross section view of the support of FIG. 27;

FIG. 29 is a partial schematic view in longitudinal section of thesupport of the present invention and of a calcified cardiac ring;

FIG. 30 is a schematic view of an alternative to the support of FIG. 29;

FIG. 31 is a schematic view of an alternative to the support of FIG. 29;

FIGS. 32 and 33 are schematic views of an alternative to the support ofFIG. 29;

FIG. 34 is a schematic cross-sectional view of a balloon correspondingto the support structure of FIGS. 19 to 21;

FIG. 35 is a schematic longitudinal sectional view of an alternativeembodiment of the balloon of FIG. 34;

FIG. 36 is a schematic view of a heart with an embodiment of the presentinventive prosthesis shown deployed in place;

FIG. 37 is a perspective view of one embodiment of a prosthetic valveassembly of the present invention;

FIG. 38 is a side view of the prosthetic valve assembly of FIG. 37;

FIG. 39 is a perspective view of one embodiment of the prosthetic valveassembly of FIG. 37;

FIG. 40 is a perspective view of an alternative embodiment of theprosthetic valve assembly with a sheath around the valve;

FIG. 41A is a perspective view of a distal portion of a catheterassembly for use in deploying the prosthetic valve assembly describedherein;

FIG. 41B is a perspective view of a proximal portion of the catheterassembly of FIG. 41A;

FIG. 42 is a perspective view of the distal portion of the catheterassembly of FIG. 41A;

FIGS. 43 through 45 are perspective views of the catheter assembly ofFIG. 41A showing deployment of a prosthesis assembly in sequence;

FIGS. 46 and 47 are perspective views of the catheter assembly of FIG.41A showing deployment of an alternative prosthesis assembly;

FIG. 48 is a perspective view of the alternative prosthesis assemblyshown in FIGS. 46 and 47.

FIG. 49 is a perspective view of an alternative embodiment of theprosthetic valve assembly of FIG. 37 showing a distal anchor;

FIG. 50 is side view of an impeller and impeller housing of oneembodiment of the blood pump;

FIG. 51 is a side view of a catheter with catheter openings that allowblood flow by the impeller;

FIG. 52 is a side view of the catheter with the impeller in place andblood flow depicted by arrows;

FIG. 53 depicts another embodiment of the invention with a separateblood pump catheter relative to the prosthesis delivery system;

FIG. 54 illustrates the embodiment shown in FIG. 16 with the blood pumpin place and blood flow shown by arrows;

FIG. 55 depicts one embodiment of the present invention comprising loopelements released from a delivery catheter after withdrawal of an outersheath;

FIGS. 56A and 56B represent one embodiment of the radial restraintcomprising a wire interwoven into the support structure;

FIG. 57 depicts another embodiment of the invention wherein two radialrestraints of different size are attached to different portions of thesupport structure;

FIG. 58 represents one embodiment of the radial restraint comprising acuff-type restraint;

FIG. 59 is a schematic view of a wire bend with a symmetrically reduceddiameter;

FIG. 60 is a schematic view of an alternative embodiment of a wire bendwith an asymmetrically reduced diameter;

FIG. 61 is a schematic view of one embodiment of the implantationprocedure for the prosthetic valve where the distal end of atransseptally placed guidewire has been externalized from the arterialcirculation;

FIG. 62 is a schematic view of a balloon catheter passed over theguidewire of FIG. 61 to dilate the native valve;

FIG. 63 is a schematic view showing the deployment of a prosthetic valveby an arterial approach over the guidewire of FIG. 62;

FIG. 64 is a schematic view showing a balloon catheter passed over theguidewire of FIG. 63 from a venous approach and placed opposite thestented native valve for additional ablation and/or securing of thelower portion of the stent;

FIG. 65 is a schematic view showing how the stent of FIG. 64 remainsattached to the delivery system by braces to allow full positioning ofthe stent;

FIG. 66 depicts a schematic view of another embodiment of theimplantation procedure for the prosthetic valve where a guidewire isinserted into the axillary artery and passed to the left ventricle;

FIG. 67 depicts a schematic view of a blood pump passed over theguidewire of FIG. 66;

FIG. 68 depicts a schematic view of a valve prosthesis passed over theblood pump of FIG. 67;

FIGS. 69 and 70 depict schematic views of the deployment and attachmentof the prosthesis of FIG. 68 to the vessel wall.

FIG. 71 is a photograph of a valve assembly with radial restraintsintegrally formed by laser cutting;

FIGS. 72A through 72C are schematic views of a portion of a valveassembly with different radial restraints formed by laser cutting;

FIGS. 73A through 73E are schematic views of another embodiment of alaser cut anti-recoil feature, in various states of expansion;

FIGS. 74A and 74B are schematic views of an angular mechanical stop forcontrolling diameter; and

FIGS. 75A and 75B are schematic views of an angular mechanical stop witha latch for resisting recoil.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to the figures wherein like parts are designatedwith like numerals throughout. FIGS. 1 to 3 represent a device 1 forreplacing a heart valve by a percutaneous route. This device comprises atubular catheter 2 formed from three tubes 5, 6, 7 engaged one insidethe other and on which there are placed, from the proximal end to thedistal end (considered with respect to the flow of blood, that is to sayfrom right to left in FIG. 1), a prosthetic valve 10, two series ofblades 11, 12, a balloon 13 and a filter 14. The three tubes 5, 6, 7 aremounted so that they can slide one inside the other. The interior tube 5delimits a passage 15, the cross section of which is large enough toallow blood to flow through it. At the proximal end, the intermediatetube 6 forms a bell housing 6 a delimiting, with the interior tube 5, anannular cavity 17 in which the prosthetic valve 10 is contained in thefurled condition.

FIG. 4 shows that this valve 10 comprises an armature 20 and valveleaflets 21 mounted so that they are functionally mobile on thisarmature 20. The armature comprises a collection of wires 22, 23, 24made of shape memory material, particularly of nickel-titanium alloyknown by the name of “NITINOL;” namely, (i) a proximal end wire 22which, when the valve 10 is in the deployed state, has a roughlycircular shape; (ii) a distal end wire 23 forming three corrugations inthe axial direction, these corrugations being distributed uniformlyaround the circumference of the valve 10, and (iii) an intermediate wire24 forming longitudinal corrugations between the wires 22 and 23, thiswire 24 being connected to the latter ones via the ends of each of thesecorrugations. The valve leaflets 21 for their part are made ofbiological material (preserved human or animal valve leaflets) or ofsynthetic material, such as a polymer. The armature 20 may, when itsmaterial is cooled, be radially contracted so that the valve 10 canenter the cavity 17. When this material is heated to body temperature,this armature 20 returns to its original shape, depicted in FIG. 4, inwhich it has a diameter matched to that of a bodily vessel, particularlythe aorta, in which the native valve that is to be treated lies. Thisdiameter of the armature 20 is such that the valve 10 bears against thewall of the bodily vessel and is immobilized in the axial direction withrespect to that vessel.

Each series of blades 11, 12 comprises metal elongate blades 30 and aninflatable balloon 31 situated between the catheter 2 and these blades30. The blades 30 have a curved profile and are arranged on thecircumference of the catheter 2, as shown in FIGS. 2, 3 and 3A. Theblades 30 of the proximal series 11 are connected pivotably to the tube6 by their proximal ends and comprise a cutting distal edge 30 a, whilethe blades 30 of the distal series 12 are connected pivotably to theexterior tube 7 by their distal ends and comprise a cutting proximaledge 30 b. The connection between the blades 30 and the respective tubes6 and 7 is achieved by welding the ends of the blades 30 together toform a ring, this ring being fixed axially to the corresponding tube 6,7 by crimping this ring onto this tube 6, 7, the pivoting of the blades30 being achieved by simple elastic deformation of these blades 30. Thispivoting can take place between a position in which the blades 30 arefurled, radially internally with respect to the catheter 2 and shown inFIGS. 1 and 2, and a position in which these blades 30 are unfurled,radially externally with respect to this catheter 2 and shown in FIG. 3.In the furled position, the blades 30 lie close to the wall of the tube6 and partially overlap each other so that they do not impede theintroduction and the sliding of the device 1 into and in the bodilyvessel in which the native valve that is to be treated lies; in saidunfurled position, the blades 30 are deployed in a corolla so that theircutting edges 30 a, 30 b are placed in the continuation of one anotherand thus constitute a circular cutting edge visible in FIG. 3.

Each balloon 31, placed between the tube 3 and the blades 30, may beinflated from the end of the catheter 2 which emerges from the patient,via a passage 32 formed in the tube 6. It thus, when inflated, allowsthe blades 30 to be brought from their furled position into theirunfurled position, and performs the reverse effect when deflated. Theaxial sliding of the tube 6 with respect to the tube 7 allows the seriesof blades 11, 12 to be moved axially toward one another, between aspaced-apart position shown in FIG. 1, and a close-together position. Inthe former of these positions, one series of blades 11 may be placedaxially on one side of the native valve while the other series of blades12 is placed axially on the other side of this valve, whereas in thelatter of these positions, the circular cutting edges of these twoseries of blades 11, 12 are brought into mutual contact and thus cutthrough the native valve in such a way as to detach it from said bodilyvessel. The tubes 5 to 7 further comprise marks (not visible in thefigures) in barium sulfate allowing the axial position of the device 1with respect to the native valve to be identified percutaneously so thateach of the two series of blades 11, 12 can be placed on one axial sideof this valve. These tubes 5 to 7 also comprise lateral distal openings(not depicted) to allow the blood to reach the bodily vessel, theseopenings being formed in such a way that the length of catheter 2through which the blood flows is as short as possible, that is to sayimmediately after the filter 14, in the distal direction.

The balloon 13 is placed on the exterior face of the tube 7, distallywith respect to the series 12. This balloon 13 has an annular shape andis shaped to be able to occupy a furled position in which it has a crosssection such that it does not impede the introduction and sliding of thedevice 1 into and in said bodily vessel, and an unfurled position, inwhich it occupies all of the space between the exterior face of the tube7 and the wall of said bodily vessel and, via a peripheral edge 13 awhich it comprises, bears against this wall.

The filter 14 is placed distally with respect to the balloon 13, on thetube 7, to which it is axially fixed. This filter 14 is made of flexiblematerial, for example polyester netting, and is shaped to be able tooccupy a furled position in which it has a cross section such that itdoes not impede the introduction and sliding of the device 1 into and insaid bodily vessel, and an unfurled position in which it occupies all ofthe space between the exterior face of the catheter 2 and the wall ofthis vessel and, via a peripheral edge 14 a which it comprises, bearsagainst this wall.

An inflatable balloon 35 is placed between the tube 7 and the filter 14so as, depending on whether it is inflated or deflated, to bring thefilter 14 into its respective unfurled and furled positions. Inpractice, as shown by FIGS. 5 to 9, the device 1 is introduced into saidbodily vessel 50 by a percutaneous route and is slid along inside thisvessel 50 until each of the series 11, 12 of blades is placed on oneside of the native valve 55 that is to be treated (FIG. 5). Thisposition is identified using the aforementioned marks. When the deviceis in this position, the proximal part of the catheter 2 is situated inthe heart, preferably in the left ventricle, while the aforementioneddistal lateral openings are placed in a peripheral arterial vessel,preferably in the ascending aorta. The balloons 13 and 35 are inflatedin such a way as to cause blood to flow only through the passage 15 andprevent blood reflux during the ablation of the valve 55. A peripheralperfusion system is set in place to facilitate this flow, as furtherdescribed below in connection with FIGS. 50 through 52. The blades 30 ofthe two series 11, 12 are then deployed (FIG. 6) by inflating theballoons 31, then these two series 11, 12 are moved closer together bysliding the tube 6 with respect to the tube 7, until the valve 55 is cutthrough (FIG. 7). The blades 30 are then returned to their furledposition by deflating the balloons 31 while at the same time remainingin their close-together position, which allows the cut-out valve 55 tobe held between them. The device 1 is then slid axially in the distaldirection so as to bring the bell housing 6 a to the appropriateposition in the vessel 50 (FIG. 8), after which the valve 10 is deployedby sliding the tube 6 with respect to the tube 5 (FIG. 9). The balloons13 and 35 are deflated then the device 1 is withdrawn and the cut-outvalve 55 is recovered (FIG. 10).

FIG. 11 shows a second embodiment of the device 1, allowing operation ona mitral valve 56. The same reference numerals are used to denote thesame elements or parts as the aforementioned, as long as these elementsor parts are identical or similar in both embodiments. In this case, thetubular catheter is replaced by a support wire 2, on which one of theseries of blades is mounted and by a tube engaged over and able to slidealong this wire, on which tube the other series of blades is mounted;the passages for inflating the balloons 31 run along this support wireand this tube; the balloon 13 and the filter 14 are separate from thedevice 1 and are introduced into the aorta via a peripheral arterialroute, by means of a support wire 40 along which the passages forinflating the balloons 13 and 35 run. The device 1, devoid of balloon 13and the filter 14, is for its part introduced into the heart through theperipheral venous system, as far as the right atrium then into the leftatrium through the inter-auricular septum, as far as the valve 56. Forthe remainder, the device 1 operates in the same way as was mentionedearlier. The invention thus provides a device for replacing a heartvalve by a percutaneous route, making it possible to overcome thedrawbacks of the prior techniques. Indeed the device 1 is entirelysatisfactory as regards the cutting-away of the valve 55, 56, making itpossible to operate without stopping the heart and making it possible,by virtue of the filter 14, to prevent any dispersion of valve fragments55, 56 into the circulatory system.

The above device may comprise a fourth tube, engaged on and able toslide along the tube 7, this fourth tube comprising the balloon and thefilter mounted on it and allowing said series of blades to be moved inthe axial direction independently of said balloon and/or of said filter;the blades may be straight as depicted in the drawing or may be curvedtoward the axis of the device at their end which has the cutting edge,so as to eliminate any risk of lesion in the wall of the bodily vessel,as shown in FIG. 12; the filter 14 may be of the self-expanding type andnormally kept in the contracted position by a sliding tube, which coversit, making the balloon 35 unnecessary.

FIGS. 13 to 16 represent tubular support 101 for positioning, bypercutaneous route, of replacement heart valve 102. The supportstructure 101 includes median portion 103, which contains valve 102, twoextreme wedging portions 104 and wires 105 for connecting these portions103 and 104. Median portion 103 also includes peripheral shell 106provided with anchoring needles 107 and shell 108 made of compressiblematerial. As is particularly apparent from FIG. 12, each of portions 103and 104 is formed with an undulating wire, and wires 105 connectpointwise the ends of the undulations of portion 103 to the end of anadjacent wave of portion 104. Portions 104, seen in expanded form, havelengths greater than the length of portion 103, so that when the ends ofthe wires respectively forming portions 103 and 104 are connected inorder to form the tubular support structure 101, the diameter of portion103 is smaller than the diameter of portions 104.

The diameter of portion 103 is such that portion 103 can, as shown byFIG. 17, support cardiac ring 110 that remains after removal of thedeficient native valve, while portions 104 support walls 111 borderingring 110. These respective diameters are preferably such that saidsupporting operations take place with slight radial restraint of ring110 and walls 111. Portion 103 presents in the deployed state a constantdiameter. Portions 104 can have a constant diameter in the form of atruncated cone whose diameter increases away from portion 103. Theentire support structure 101 can be made from a material with shapememory, such as the nickel-titanium alloy known as “Nitinol.” Thismaterial allows the structure to be contracted radially, as shown inFIG. 16, at a temperature different from that of the body of the patientand to regain the original shape shown in FIGS. 14 and 15 when itstemperature approaches or reaches that of the body of the patient. Theentire support structure 101 can also be made from a material that canbe expanded using a balloon, such as from medical stainless steel (steel316 L). Valve 102 can be made of biological or synthetic tissue. It isconnected to portion 103 by sutures or by any other appropriate means ofattachment. It can also be molded on portion 103. Shell 106 may be madeof “Nitinol.” It is connected to the undulations of portion 103 atmid-amplitude, and has needles 107 at the site of its regions connectedto these undulations. Needles 107 consist of strands of metallic wirepointed at their free ends, which project radially towards the exteriorof shell 106.

This shell can take on the undulating form that can be seen in FIG. 16in the contracted state of support 101 and the circular form which canbe seen in FIG. 4 in the deployed state of this support 101. In itsundulating form, shell 106 forms undulations 106 a projecting radiallyon the outside of support 101, beyond needles 107, so that these needles107, in the retracted position, do not obstruct the introduction ofsupport 101 in a catheter or, once support 101 has been introduced intothe heart using this catheter, do not obstruct the deployment out ofthis support 1. The return of shell 106 to its circular form bringsneedles 107 to a position of deployment, allowing them to be inserted inring 110 in order to complete the anchoring of support 101. Shell 108 isattached on shell 106. Its compressible material allows it to absorb thesurface irregularities that might exist at or near ring 110 and thus toensure complete sealing of valve 102.

FIG. 18 shows a support structure 101 having a single portion 104connected to portion 103 by wires 105. This portion 104 is formed by twoundulating wires 114 connected together by wires 115. FIG. 19 shows asupport structure 101 that has portion 103 and portion 104 connected byconnecting wires 105. These portions 103 and 104 have diamond-shapedmesh structures, these mesh parts being juxtaposed in the direction ofthe circumference of these portions and connected together at the siteof two of their opposite angles in the direction of the circumference ofthese portions 103 and 104. Wires 105 are connected to these structuresat the site of the region of junction of two consecutive mesh parts.These mesh parts also have anchoring hooks 107 extending through themfrom one of their angles situated in the longitudinal direction ofsupport 101.

FIG. 20 illustrates, in an enlarged scale, the structure of this portion104 and of a part of wires 105, as cut, for example, with a laser from acylinder of stainless steel, and after bending of sharp ends 107 a ofhooks 107. These hooks, in a profile view, can have the shape as shownin FIG. 24 or 26. The structure represented in FIG. 19 also has axialholding portion 120, which has a structure identical to that of portion104 but with a coarser mesh size, and three wires 105 of significantlength connecting this portion 120 to portion 103. These wires 105, onthe side of portion 120, have a single link 105 a and on the side ofportion 103, a double link 105 b. Their number corresponds to the threejunctions formed by the three valves of valve 102, which facilitatesmounting of valve 102 on support 101 thus formed. The support accordingto FIG. 19 is intended to be used, as appears in FIG. 21, when the bodypassage with the valve to be replaced, in particular the aorta, has avariation in diameter at the approach to the valve. The length of wires105 connecting portions 103 and 120 is provided so that afterimplantation, portion 120 is situated in a non-dilated region of saidbody passage, and this portion 120 is provided so as to engage the wallof the passage.

FIG. 22 shows a structure similar to that of FIG. 19 but unexpanded,except that the three wires 105 have a single wire structure but have anundulating wire 121 ensuring additional support near portion 103. Thiswire 121 is designed to support valve 102 with three valve leaflets.FIGS. 23 to 26 show an embodiment variant of the structure of portions103, 104 or 120, when this structure is equipped with hooks 107. In thiscase, the structure has a zigzagged form, and each hook 107 has two arms107 b; each of these arms 107 b is connected to the other arm 107 b atone end and to an arm of structure 101 at its other end. The region ofjunction of the two arms 107 b has bent hooking pin 107 a.

FIG. 27 shows portion 103 that has two undulating wires 125, 126extending in the vicinity of one another and secondary undulating wire127. As represented in FIG. 28, wires 125, 126 can be used to executethe insertion of valve 102 made of biological material between them andthe attachment of this valve 102 to them by means of sutures 127. FIG.29 shows a part of support 101 according to FIGS. 13 to 17 and the wayin which the compressible material constituting shell 108 can absorb thesurface irregularities possibly existing at or near ring 110, whichresult from calcifications. FIG. 30 shows support 101 whose shell 106has no compressible shell. A material can then be applied, by means ofan appropriate cannula (not represented), between ring 110 and thisshell 106, this material being able to solidify after a predetermineddelay following application.

FIG. 31 shows support 101 whose shell 106 has a cross section in theform of a broken line, delimiting, on the exterior radial side, a lowershoulder. Housed in the step formed by this shoulder and the adjacentcircumferential wall is peripheral shell 108 which can be inflated bymeans of a catheter (not represented). This shell 108 delimits a chamberand has a radially expandable structure, such that it has in crosssection, in the inflated state, two widened ends projecting on bothsides of shell 106. This chamber can receive an inflating fluid that cansolidify in a predetermined delay following its introduction into saidchamber. Once this material has solidified, the inflating catheter iscut off.

FIGS. 32 and 33 show support 101 whose shell 106 receives inflatableinsert 108 which has a spool-shaped cross section in the inflated state;this insert 108 can be inflated by means of catheter 129. Insert 108 ispositioned in the uninflated state (FIG. 32) at the sites in which aspace exists between shell 106 and existing cardiac ring 110. Its spoolshape allows this insert (cf. FIG. 33) to conform as much as possible tothe adjacent irregular structures and to ensure a better seal.

FIG. 34 shows balloon 130 making it possible to deploy support 101according to FIGS. 19 to 21. This balloon 130 has cylindrical portion131 whose diameter in the inflated state makes possible the expansion ofholding portion 120, a cylindrical portion 132 of lesser diameter,suitable for producing the expansion of portion 103, and portion 133 inthe form of a truncated cone, makes possible the expansion of portion104. As shown by FIG. 35, portion 132 can be limited to what is strictlynecessary for deploying portion 103, which makes it possible to produceballoon 130 in two parts instead of a single part, thus limiting thevolume of this balloon 130.

FIG. 36 shows support 101 whose median portion 103 is in two parts 103a, 103 b. Part 103 a is made of undulating wire with large-amplitudeundulations, in order to support valve 102, and part 103 b, adjacent tosaid part 103 a and connected to it by bridges 135, is made ofundulating wire with small-amplitude undulations. Due to its structure,this part 103 b presents a relatively high radial force of expansion andis intended to be placed opposite ring 110 in order to push back thenative valve sheets which are naturally calcified, thickened andindurated, or the residues of the valve sheets after valve resectionagainst or into the wall of the passage. This axial portion 103 a, 103 bthus eliminates the problem induced by these sheets or residual sheetsat the time of positioning of valve 102.

It is apparent from the preceding that one embodiment of the inventionprovides a tubular support for positioning, by percutaneous route, of areplacement heart valve, which provides, due to its portions 103 and104, complete certitude as to its maintenance of position afterimplantation. This support also makes possible a complete sealing of thereplacement valve, even in case of a cardiac ring with a surface that isto varying degrees irregular and/or calcified, and its position can beadapted and/or corrected as necessary at the time of implantation.

Referring to FIGS. 37 and 38, the present invention also comprises analternative prosthetic valve assembly 310, which further comprises aprosthetic valve 312, a valve support band 314, distal anchor 316, and aproximal anchor 318. Valve 312 can be made from a biological material,such as one originating from an animal or human, or from a syntheticmaterial, such as a polymer. Depending upon the native valve to bereplaced, the prosthetic valve 312 comprises an annulus 322, a pluralityof leaflets 324 and a plurality of commissure points 326. The leaflets324 permit the flow of blood through the valve 312 in only onedirection. In the preferred embodiment, the valve annulus 322 and thecommissure points 326 are all entirely supported within the centralsupport band 314. Valve 312 is attached to the valve support band 314with a plurality of sutures 328, which can be a biologically compatiblethread. The valve could also be supported on band 314 with adhesive,such as cyanoacrylate.

In one embodiment, valve 312 can be attached to, or may integral with, asleeve or sheath 313. The sheath is secured to the valve support band314 such that the outer surface of the sheath is substantially incontact with the inner surface of the valve support band 314. In suchembodiment, the sheath can be attached to the valve support band 314with sutures 328. FIG. 40 is a schematic of the concept of thisalternative embodiment. If desired, the sheath 313 can be secured to theoutside of valve support band 314 (not shown).

Referring to FIGS. 37 and 38, in one embodiment, valve support band 314is made from a single wire 342 configured in a zigzag manner to form acylinder. Alternatively, valve support band 314 can be made from aplurality of wires 342 attached to one another. In either case, the bandmay comprise one or more tiers, each of which may comprise one or morewires arranged in a zigzag manner, for structural stability ormanufacturing ease, or as anatomical constraints may dictate. Ifdesired, even where the central valve support 314 is manufactured havingmore than one tier, the entire valve support 314 may comprise a singlewire. Wire 342 can be made from, for example, stainless steel, silver,tantalum, gold, titanium or any suitable plastic material. Valve supportband 314 may comprise a plurality of loops 344 at opposing ends topermit attachment to valve support band 314 of anchors 316 and/or 318with a link. Loops 344 can be formed by twisting or bending the wire 342into a circular shape. Alternatively, valve support band 314 and loops344 can be formed from a single wire 342 bent in a zigzag manner, andtwisted or bent into a circular shape at each bend. The links can bemade from, for example, stainless steel, silver, tantalum, gold,titanium, any suitable plastic material, solder, thread, or suture. Theends of wire 342 can be joined together by any suitable method,including welding, gluing or crimping.

Still referring to FIGS. 37 and 38, in one embodiment, distal anchor 316and proximal anchor 318 each comprise a discrete expandable band madefrom one or more wires 342 bent in a zigzag manner similar to thecentral band. Distal anchor band 316 and proximal anchor band 318 maycomprise a plurality of loops 344 located at an end of wire 342 so thatdistal anchor band 316 and proximal anchor band 318 can each be attachedto valve support band 314 with a link. Loop 344 can be formed bytwisting or bending the wire 342 into a circular shape. As desired,distal and/or proximal anchors 316, 318 may comprise one or more tiers,as explained before with the valve support 314. Likewise, each anchormay comprise one or more wires, regardless of the number of tiers. Asexplained above in regard to other embodiments, the distal anchor may beattached to the central valve support band 314 directly, as in FIG. 37,or spaced distally from the distal end of the valve support 314, asshown above schematically in FIGS. 18, 19, 21 and 22. In the laterinstance, one or more struts may be used to link the distal anchor bandto the valve support band, as described above.

Distal anchor band 316 has a first end 350 attached to the central valveband 314, and a second end 352. Similarly, proximal anchor band 318 hasfirst attached end 354 and a second end 356. The unattached ends 352,356 of the anchors 316, 318, respectively are free to expand in a flaredmanner to conform to the local anatomy. In such embodiment, the distaland proximal anchor bands 316, 318 are configured to exert sufficientradial force against the inside wall of a vessel in which it can beinserted. Applying such radial forces provides mechanical fixation ofthe prosthetic valve assembly 310, reducing migration of the prostheticvalve assembly 310 once deployed. It is contemplated, however, that theradial forces exerted by the valve support 314 may be sufficient toresist more than a minimal amount of migration, thus avoiding the needfor any type of anchor.

In an alternative embodiment, distal and proximal anchors may comprise afixation device, including barbs, hooks, or pins (not shown). Suchdevices may alternatively or in addition be placed on the valve support314. If so desired, the prosthetic valve assembly 310 may comprise anadhesive on the exterior thereof to adhere to the internal anatomicallumen.

Prosthetic valve assembly 310 is compressible about its center axis suchthat its diameter may be decreased from an expanded position to acompressed position. When placed into the compressed position, valveassembly 310 may be loaded onto a catheter and transluminally deliveredto a desired location within a body, such as a blood vessel, or adefective, native heart valve. Once properly positioned within the bodythe valve assembly 310 can be deployed from the compressed position tothe expanded position. FIG. 39 is a schematic of one embodiment of theprosthetic valve assembly described with both distal and proximal anchorbands 316, 318 while FIG. 49 is a schematic showing only a distal anchor316.

In the preferred embodiment, the prosthetic valve assembly 310 is madeof self-expanding material, such as Nitinol. In an alternativeembodiment, the valve assembly 310 requires active expansion to deployit into place. Active expansion may be provided by an expansion devicesuch as a balloon.

As referred to above in association with other embodiments, theprosthetic valve assembly of the present invention is intended to bepercutaneously inserted and deployed using a catheter assembly.Referring to FIG. 41A, the catheter assembly 510 comprises an outersheath 512, an elongate pusher tube 514, and a central tube 518, each ofwhich are concentrically aligned and permit relative movement withrespect to each other. At a distal end of the pusher tube 514 is apusher tip 520 and one or more deployment hooks 522 for retaining theprosthesis assembly (not shown). The pusher tip 520 is sufficientlylarge so that a contracted prosthesis assembly engages the pusher tip520 in a frictional fit arrangement. Advancement of the pusher tube 514(within the outer sheath 512) in a distal direction serves to advancethe prosthesis relative to the outer sheath 512 for deployment purposes.

At a distal end of the central tube 518 is an atraumatic tip 524 forfacilitating the advancement of the catheter assembly 510 through thepatient's skin and vasculature. The central tube 518 comprises a centrallumen (shown in phantom) that can accommodate a guide wire 528. In oneembodiment, the central lumen is sufficiently large to accommodate aguide wire 528 that is 0.038 inch in diameter. The guide wire can slidethrough the total length of the catheter form tip to handle (‘over thewire’ catheter) or the outer sheath 512 can be conformed so as to allowfor the guide wire to leave the catheter before reaching its proximalend (‘rapid exchange’ catheter). The space between the pusher tube 514and the outer sheath 512 forms a space within which a prosthetic valveassembly may be mounted.

Hooks 522 on the distal end of the pusher tube 514 may be configured inany desired arrangement, depending upon the specific features of theprosthetic assembly. With regard to the prosthesis assembly of FIGS. 37and 38, the hooks 522 preferably comprise an L-shaped arrangement toretain the prosthesis assembly axially, but not radially. With aself-expanding assembly, as the prosthesis assembly is advanced distallybeyond the distal end of the outer sheath 512, the exposed portions ofthe prosthesis assembly expand while the hooks 522 still retain theportion of the prosthesis still housed within the outer sheath 512. Whenthe entire prosthesis assembly is advanced beyond the distal end of theouter sheath, the entire prosthesis assembly is permitted to expand,releasing the assembly from the hooks. FIGS. 42 through 45 show thedistal end of one embodiment of the catheter assembly, three of whichshow sequenced deployment of a valve prosthesis.

FIG. 48 shows an alternative embodiment of the valve prosthesis, whereloop elements extend axially from one end of the prosthesis and areretained by the hooks 522 on pusher tube 514 during deployment. FIGS. 46and 47 show a catheter assembly used for deploying the alternativeprosthesis assembly of FIG. 48. By adding loop elements to theprosthesis, the prosthesis may be positioned with its support andanchors fully expanded in place while permitting axial adjustment intofinal placement before releasing the prosthesis entirely from thecatheter. Referring to FIG. 55, an alternative embodiment of aself-expanding valve prosthesis and delivery system comprises loopelements 694 on prosthetic assembly 310 retained by disks 696 on pushertube 514 by outer sheath 512. When outer sheath 512 is pulled back toexpose disks 696, self-expanding loop elements 694 are then releasedfrom pusher tube 514.

FIG. 41B shows the proximal end of the catheter assembly 510 that, to agreater extent, has many conventional features. At the distal end of thepusher tube 514 is a plunger 530 for advancing and retreating the pushertube 514 as deployment of the prosthesis assembly is desired. Asdesired, valves and flush ports proximal and distal to the valveprosthesis may be provided to permit effective and safe utilization ofthe catheter assembly 510 to deploy a prosthesis assembly.

In one embodiment, prosthetic valve assembly 310 (not shown) is mountedonto catheter 510 so that the valve assembly 310 may be delivered to adesired location inside of a body. In such embodiment, prosthetic valveassembly 310 is placed around pusher tip 520 and compressed radiallyaround the tip 520. The distal end of prosthetic valve assembly 310 ispositioned on the hooks 522. While in the compressed position, outersheath 512 is slid toward the atraumatic tip 524 until it substantiallycovers prosthetic valve assembly 310.

To deliver prosthetic valve assembly 310 to a desired location withinthe body, a guide wire 528 is inserted into a suitable lumen of thebody, such as the femoral artery or vein to the right atrium, then tothe left atrium through a transseptal approach, and maneuvered,utilizing conventional techniques, until the distal end of the guidewire 528 reaches the desired location. The catheter assembly 510 isinserted into the body over the guide wire 528 to the desired position.Atraumatic tip 524 facilitates advancement of the catheter assembly 510into the body. Once the desired location is reached, the outer sheath512 is retracted permitting the valve prosthesis to be released fromwithin the outer sheath 512, and expand to conform to the anatomy. Inthis partially released state, the position of prosthetic valve 310 maybe axially adjusted by moving catheter assembly 510 in the proximal ordistal direction.

It is apparent that the invention advantageously contemplates aprosthesis that may have a non-cylindrical shape, as shown in severalearlier described embodiments including but not limited to FIGS. 21,37-40, 49 and 59. This non-cylindrical shape results from controllingthe diameters at some portions of prosthetic valve assembly 310.Referring to FIG. 56A, yet another non-cylindrical prosthesis is shown.Central support band 314 comprises a diameter-restrained portion ofvalve assembly 310 attached to distal and proximal anchors 316, 318,that comprise discrete self-expandable bands capable of expanding to aflared or frusta-conical configuration. Anchors 316, 318 furtheraccentuate the non-cylindrical shape of central support band 314. FIG.56A shows one embodiment of the invention for limiting the diameter ofportions of the valve assembly 310 from excessive expansion, wherebyvalve assembly 310 further comprises a radial restraint 690 to limit thediameter of central support band 314. Radial restraint, as used herein,shall mean any feature or process for providing a desired diameter orrange of diameters, including but not limited to the selection ofmaterials or configurations for valve assembly 310 such that it does notexpand beyond a preset diameter. Controlling radial expansion to apreset diameter at central support band 314 helps maintain thecoaptivity of valve 312 and also preserves the patency of the coronaryostia by preventing central support band 314 from fully expanding to thelumen or chamber wall to cause occlusion. Restraint 690 may besufficiently flexible such that restraint 690 may contract radially withvalve assembly 310, yet in the expanded state resists stretching beyonda set limit by the radial expansion forces exerted by a self-expandingvalve assembly 310 or from a balloon catheter applied to valve assembly310. Referring to FIG. 56A and 56B, restraint 690 may take any of avariety of forms, including wires 700 of a specified length that joinportions of central support band 314. Threads may also be used forradial restraint 690. The slack or bends in the wires allow a limitedradial expansion to a maximum diameter. Once the slack is eliminated orthe bends are straightened, further radial expansion is resisted bytension created in wires 700. These wires may be soldered, welded orinterwoven to valve assembly 310. By changing the length of wire joiningportions of valve assembly 310, radial restraints of different maximumdiameters are created. For example, by using short wires to form theradial restraint, the valve support structure may expand a shorterdistance before tension forms in the short wires. If longer wires areused, the support structure may expand farther before tension developsin the longer wires.

FIG. 57 depicts central support band 314 with a radial restraint 700 ofa smaller diameter and another portion of the same valve assembly 310with longer lengths of wire 701 and allowing a larger maximum diameter.The portion of valve assembly 310 with the larger diameter can beadvantageously used to allow greater dilation around cardiac ring 110and native valve sheets. The degree of resistance to expansion orrecollapse can be altered by changing the diameter of the radialrestraint or by changing the configuration of the restraint. Forexample, a cross-linked radial restraint will have a greater resistanceto both expansion and recollapse. Referring to FIG. 58, restraint 690may alternatively comprise a cuff 691 encompassing a circumference ofcentral support band 314 that resists expansion of central support band314 beyond the circumference formed by cuff 691. Cuff 691 may be made ofePTFE or any other biocompatible and flexible polymer or material as isknown to those skilled in the art. Cuff 691 may be attached to valveassembly 310 by sutures 692 or adhesives.

FIG. 71 illustrates one embodiment of the invention where radialrestraints are integrally formed as part of valve assembly 310 by usinga laser cutting manufacturing process, herein incorporated by reference.FIG. 72A depicts a schematic view of a laser-cut portion of valveassembly 310 in the unexpanded state with several radial restraints 706,708, 710. Each end of radial restraints 706, 708, 710 is integrallyformed and attached to valve assembly 310. An integrally formed radialrestraint may be stronger and may have a lower failure rate compared toradial restraints that are sutured, welded or soldered to valve assembly310. FIG. 72B depicts a shorter radial restraint 706 along onecircumference of valve assembly 310. FIG. 72C depicts another portion ofvalve assembly 310 with a longer radial restraint 708 and a cross-linkedradial restraint 710 positioned along the same circumference. Thus, thesegments of a radial restraint along a given circumference need not havethe same characteristics or size.

Another embodiment of the radial restraint comprises at least oneprotrusion extending from valve assembly 310 to provide a mechanicalstop arrangement. The mechanical stop arrangement restricts radialexpansion of valve assembly 310 by using the inverse relationshipbetween the circumference of valve assembly 310 and the length of valveassembly 310. As valve assembly 310 radially expands, the longitudinallength of valve assembly 310 may contract or compress as the diameter ofvalve assembly 310 increases, depending upon the particular structure orconfiguration used for valve assembly 310. For example, FIGS. 37, 38,56A, 57 and 71 depict embodiments of the invention wherein valveassembly 310 comprises a diamond-shaped mesh. The segments of the meshhave a generally longitudinal alignment that reorient to a morecircumferential alignment during radial expansion of valve assembly 310.By limiting the distance to which valve assembly 310 can compress in alongitudinal direction, or by restricting the amount of angularreorientation of the wires of valve assembly 310, radial expansion inturn may be controlled to a pre-set diameter. FIG. 74A shows oneembodiment of the mechanical stop arrangement comprising an angular stop730 and an abutting surface 732 on the wire structure of valve assembly310. A plurality of stops 730 and abutting surfaces 732 may be usedalong a circumference of valve assembly 310 to limit expansion to apreset diameter. Angular stop 730 may be located between two adjoiningportions of valve assembly 310 forming an angle that reduces with radialexpansion. As shown in FIG. 74B, as valve assembly 310 radially expands,angular stop 730 will come in closer proximity to surface 732 andeventually abut against surface 732 to prevent further diameterexpansion of valve assembly 310. The angular size 734 of stop 730 can bechanged to provide different expansion limits. The radial size 736 ofstop 730 can also be changed to alter the strength of stop 730. Oneskilled in the art will understand that many other configurations may beused for valve assembly 310 besides a diamond-shape configuration. Forexample, FIGS. 15 and 16 depict support 101 with an undulating wirestent configuration that exhibits minimal longitudinal shortening whenexpanding. The mechanical stop arrangements described above may beadapted by those skilled in the art to the undulating wire stentconfiguration, or any other stent configuration, for controlling thediameter of the support structure or valve assembly 310.

The particular method of maintaining the valve diameter within a presetrange described previously relates to the general concept of controllingthe expanded diameter of the prosthesis. The diameter attained by aportion of the prosthesis is a function of the radial inward forces andthe radial expansion forces acting upon that portion of the prosthesis.A portion of the prosthesis will reach its final diameter when the netsum of these forces is equal to zero. Thus, controlling the diameter ofthe prosthesis can be addressed by changing the radial expansion force,changing the radial inward forces, or a combination of both. Changes tothe radial expansion force generally occur in a diameter-related mannerand can occur extrinsically or intrinsically. Radial restraint 690, cuff691 and mechanical stop 730 of FIGS. 56A, 58 and 74A, respectively, areexamples of extrinsic radial restraints that can limit or resistdiameter changes of prosthetic valve assembly 310 once a preset diameteris reached.

Other ways to control diameter may act intrinsically by controlling theexpansion force so that it does not expand beyond a preset diameter.This can be achieved by the use of the shape memory effect of certainmetal alloys like Nitinol. As previously mentioned, when a Nitinolprosthesis is exposed to body heat, it will expand from a compresseddiameter to its original diameter. As the Nitinol prosthesis expands, itwill exert a radial expansion force that decreases as the prosthesisexpands closer to its original diameter, reaching a zero radialexpansion force when its original diameter is reached. Thus, use of ashape memory alloy such as Nitinol is one way to provide an intrinsicradial restraint. A non-shape memory material that is elasticallydeformed during compression will exhibit similar diameter-dependentexpansion forces when returning to its original shape.

The other way of controlling diameter mentioned previously is to alterthe radial inward or recoil forces acting upon the support orprosthesis. Recoil forces refer to any radially inward force acting uponthe valve assembly that prevents the valve support from maintaining adesired expanded diameter. Recoil forces include but are not limited toradially inward forces exerted by the surrounding tissue and forcescaused by elastic deformation of prosthetic valve assembly 310.Countering or reducing recoil forces help to ensure deployment ofprosthetic valve assembly 310 to the desired diameter or diameter range,particularly at the native valve. For example, when the prosthetic valveassembly 310 of FIGS. 37, 38, 56A, 57 and 58 is deployed, some recoil ordiameter reduction may occur that can prevent portions of valve assembly310 from achieving it pre-set or desired diameter. This recoil can bereduced by applying an expansion force, such as with a balloon, thatstresses the material of valve assembly 310 beyond its yield point tocause plastic or permanent deformation, rather than elastic or transientdeformation. Similarly, balloon expansion can be used to further expanda self-expanded portion of valve assembly 310 where radially inwardanatomical forces have reduced the desired diameter of that portion.Balloon expansion of a self-expanded portion of valve assembly 310beyond its yield point provides plastic deformation to a largerdiameter.

In addition to the use of a balloon catheter to deform valve assembly310 beyond its yield point, other means for reducing recoil arecontemplated. In the preferred embodiment of the invention, a separatestent may be expanded against cardiac ring 110 in addition or in placeof valve assembly 310. The separate stent may further push back thenative valve sheets or residues of the resected valve and reduce therecoil force of these structures on valve assembly 310. If the separatestent is deployed against cardiac ring 110 prior to deployment of valveassembly 310, a higher radial force of expansion is exerted against ring110 without adversely affecting the restrained radial force of expansiondesired for the central support band 314 supporting valve 312.Alternatively, the separate stent may be deployed after valve assembly310 and advantageously used to reduce the recoil of valve assembly 310caused by the elastic deformation of the material used to form valveassembly 310. The separate stent may be self-expanding orballoon-expandable, or a combination thereof.

Another means for addressing recoil involves providing the radialrestraint and mechanical stop arrangements previously described with anadditional feature that forms an interference fit when the valveassembly 310 is at its preset diameter. By forming an interference fit,the radial restraint or mechanical stop will resist both furtherexpansion and recollapse from recoil. FIGS. 73A through 73E depict anembodiment of a radial restraint with a recoil-resistant configurationintegrally formed with valve assembly 310. In this embodiment, eachsegment of the radial restraint comprises a pair of protrusions 712having a proximal end 714 and a distal end 716. Proximal end 714 isintegrally formed and attached to valve assembly 310 while distal end716 is unattached. Each pair of protrusions 712 is configured so thatdistal end 716 of one protrusion 712 is in proximity to the proximal end714 of other protrusion 712 in the unexpanded state, and where distalends 716 come close together as valve assembly 310 radially expands.Distal ends 716 comprise a plurality of teeth 718 for providing aninterference fit between distal ends 716 upon contact with each other.The interference fit that is formed will resist both further radialexpansion and collapse of valve assembly 310. As mentioned earlier,collapse may result from the inherent elastic properties of thematerials used for valve assembly 310 or from radially inward forcesexerted by the tissue surrounding valve assembly 310. The interferencefit may be provided over a range of expansion, as depicted in FIGS. 72Band 72C from the self-expanded state through the extra-expanded state.This allows the inference fit to act even when a self-expanded valveassembly 310 is further expanded by a balloon catheter to anextra-expanded state as the expansion diameter is further adjusted. Thelengths of protrusions 712 will determine the amount of radial restraintprovided. Shorter protrusions 712 have distal ends 716 that contact eachother after a shorter distance of radial expansion, while longerprotrusions 712 will form an interference fit after a longer distance.

FIGS. 75A and 75B depict another embodiment of a radial restraint with arecoil resistant feature. Angular stop 730 from FIGS. 74A and 74B isprovided with a notch 736 that forms an interference fit with a latch738 protruding from valve assembly 310 adjacent to surface 732. As valveassembly 310 expands, angular stop 730 will eventually abut against tosurface 732 to prevent further expansion. Latch 738 will also movecloser to notch 736 as valve assembly 310 expands. When the presetdiameter is reached, latch 738 forms an interference fit with notch 736that resists collapse to a smaller diameter. It is contemplated that aballoon catheter may be used to expand valve assembly 310 to the desireddiameter and to engage latch 738 to notch 736.

Although both shape memory and non-shape memory based prostheses providediameter-dependent expansion forces that reach zero upon attaining theiroriginal shapes, the degree of force exerted can be further modified byaltering the thickness of the wire or structure used to configure thesupport or prosthesis. A prosthesis can be configured with thicker wiresto provide a greater expansion force to resist, for example, greaterradial inward forces located at the native valve site, but the greaterexpansion force will still reduce to zero upon the prosthesis attainingits preset diameter. Changes to wire thickness need not occur uniformlythroughout a support or prosthesis. Wire thickness can vary betweendifferent circumferences of a support or prosthesis, or between straightportions and bends of the wire structure. As illustrated in FIG. 59, thedecreased diameter 702 may be generally symmetrical about thelongitudinal axis of the wire. Alternatively, as in FIG. 60, thedecreased diameter 704 may be asymmetrical, where the diameter reductionis greater along the lesser curvature of the wire bend or undulationrelative to the longitudinal axis of the wire. At portions of theprosthesis where the exertion of a particular expansion force againstsurrounding tissue has importance over the actual diameter attained bythat portion of the prosthesis, the various methods for controllingdiameter can be adapted to provide the desired expansion force. Theseportions of the prosthesis may include areas used for anchoring andsealing such as the axial wedging portions or anchors previouslydescribed.

Referring to FIG. 61, a method for deploying the preferred embodiment ofthe invention using the separate stent is provided. The method ofdeployment comprises a guidewire 640 inserted via a venous approach 642and passed from the right 644 to left atrium 646 through a knowntransseptal approach, herein incorporated by reference. Aftertransseptal puncture, guidewire 640 is further directed from left atrium646 past the mitral valve 648 to the left ventricle 650 and through theaortic valve 652. An introducer (not shown) is inserted via an arterialapproach and a snare (not shown), such as the Amplatz GOOSE NECK® snare(Microvena, Minn.), is inserted through the introducer to grasp thedistal end of guidewire 640 and externalize guidewire 640 out of thebody through the introducer. With both ends of guidewire 640 external tothe body, access to the implantation site is available from both thevenous 642 and arterial approaches 654. In FIG. 62, aortic valve 652 ispre-dilated by a balloon catheter 656 using a well-known valvuloplastyprocedure, herein incorporated by reference. The prosthesis is thenimplanted as previously described by passing the delivery system fromeither the venous or arterial approaches. As illustrated in FIG. 63, theprosthesis 658 may be implanted using arterial approach 654 withprosthetic valve 658 implanted above the level of native valve 652. Asshown in FIG. 64, a balloon catheter 660 may be passed by venousapproach 642 for further displacement of native valve 652 and/or tofurther secure the lower stent 662 to the annulus. Hooks 664, shown inFIG. 65, connecting the delivery catheter to prosthetic valve 658 allowfull control of prosthetic valve 658 positioning until the operatorchooses to fully release and implant prosthetic valve 658. A separatestent may then be implanted by venous approach 642 at the valvular ringto further push back the native valve or valve remnants and reducerecoil forces from these structures. Passing balloon 660 by the venousapproach 642 avoids interference with superiorly located prostheticvalve 658. Implantation of replacement valve 658 by arterial approach654 prior to the ablation of the native valve 652 or valve remnants byvenous approach 642 may reduce the risks associated with massive aorticregurgitation when native valve 652 is pushed back prior to implantationof replacement valve 658. Reducing the risks of massive aorticregurgitation may provide the operator with additional time to positionreplacement valve 658.

It is further contemplated that in the preferred embodiment of theinvention, valve assembly 310 also comprises a drug-eluting componentwell known in the art and herein incorporated by reference. Thedrug-eluting component may be a surface coating or a matrix systembonded to various portions of valve assembly 310, including but notlimited to central support band 314, anchors 316 318, valve 312, loopelements 352 or wires 342. The surface coating or matrix system may havea diffusion-type, erosive-type or reservoir-based drug releasemechanism. Drugs comprising the drug-eluting component may includeantibiotics, cellular anti-proliferative and/or anti-thrombogenic drugs.Drugs, as used herein, include but are not limited to any type ofbiologically therapeutic molecule. Particular drugs may include but arenot limited to actinomycin-D, batimistat, c-myc antisense,dexamethasone, heparin, paclitaxel, taxanes, sirolimus, tacrolimus andeverolimus.

As previously mentioned, one embodiment of the system for implanting theprosthesis and/or excising the native valve leaflets contemplatesmaintaining blood flow across the native valve site during the excisionand implantation procedure. By maintaining blood flow across the nativevalve, use of extracorporeal circulation or peripheral aorto-venousheart assistance and their side effects may be reduced or avoided. Majorside effects of extracorporeal circulation and peripheral aorto-venousheart assistance include neurological deficits, increased bleeding andmassive air emboli. FIGS. 50 through 52 depict one embodiment of theinvention for maintaining blood perfusion during the procedure. Thisembodiment comprises a blood pump 600 and an opening 602 positioned inthe wall of tubular catheter 2 of the excision system. When the tubularcatheter 2 is positioned at the excision site, blood pump 600 allowscontinued blood flow across the excision site that would otherwise beinterrupted during the excision procedure. Blood pump 600 may comprise amotor, a shaft and an impeller. Blood pump 600 is insertable throughpassage 15 of tubular catheter 2. The motor is connected to a shaft 604that in turn is coupled to an impeller 606. The motor is capable ofrotating shaft 604, resulting in the rotation of impeller 606. Impeller606 comprises a proximal end 608, a distal end 610 and a plurality offins 612 angled along the longitudinal axis of impeller 606, such thatwhen impeller 606 is rotated in one direction, fins 612 are capable ofmoving blood from a proximal to distal direction. When impeller 606 isrotated in the other direction, fins 612 are capable of moving blood ina distal to proximal direction. The ability to rotate impeller 606 ineither direction allows but is not limited to the use of the blood pumpin both anterograde and retrograde approaches to a heart valve. Theblood pump is positioned generally about catheter opening 602. The bloodpump has an external diameter of about 4-mm and the passage of thecatheter has a 4-mm internal diameter. Catheter opening 602 has alongitudinal length of about 4-mm. Catheter opening 602 may comprise aplurality of openings located along a circumference of tubular catheter2. To reduce interruption of blood flow through tubular catheter 2during the implantation portion of the procedure, catheter opening 602should preferably be about 30 mm from the tip of catheter 2 or distal tothe bell housing 6 a. This positioning of catheter opening 602 reducesthe risk of occlusion of catheter opening 602 by the replacement valve.

FIG. 50 depicts an optional feature of blood pump 600 further comprisingan impeller housing 614 having at least one proximal housing opening 616and at least one distal housing opening 618. Housing 614 protectspassage 15 of tubular catheter 2 from potential damage by rotatingimpeller 600. Proximal 616 and distal housing openings 618 provideinflow and outflow of blood from the impeller, depending on the rotationdirection of impeller 600.

To reduce interruption of blood flow through catheter 2 during theimplantation portion of the procedure, catheter opening 602 shouldpreferably be at least a distance of about 30 mm from the distal tip ofthe catheter or about distal to the bell housing 6 a to avoid occlusionof catheter opening 602 by the replacement valve.

FIGS. 53 and 54 depict an alternative embodiment, where blood pump 620is located in a second catheter 622 in the prosthesis delivery system.Once blood pump 620 and second catheter 622 are in position, theprosthesis delivery system 624 is slid over the separate catheter 622 toposition the prosthesis for implantation, while avoiding blockage ofblood flow in separate catheter 622. In this embodiment, the diameter ofthe delivery system is preferably about 8 mm.

One method of using the blood flow pump during the implantation of theprosthesis is now described. This procedure may be performed underfluoroscopy and/or transesophageal echocardiography. FIG. 66 showsvascular access made through the axillary artery 666. A guidewire 668 isinserted past the aortic valve 670 and into the left ventricle 672. InFIG. 67, a blood pump 674 is inserted into a hollow catheter passed 676over guidewire 668 inside the aorta 678 and pushed into left ventricle672. Blood pump 674 is started to ensure a steady and sufficient bloodflow of about 2.5 L/min from left ventricle 672 downstream during thevalve replacement. FIG. 68 depicts valve prosthesis 680, retained on thedelivery system 682 and positioned by sliding over blood pump catheter676. Prosthesis 680 is positioned generally about the valve annulus 684and the coronary ostia 686, with the assistance of radiographic markers.As shown in FIGS. 69 and 70, the sheath 688 overlying prosthesis 680 ispulled back and prosthesis 680 is deployed as previously describedCatheter hooks 690 connecting the delivery catheter to the prostheticvalve allow full control of prosthetic valve positioning until theoperator chooses to fully release and implant the prosthetic valve.Optional anchoring hooks, described previously, may be deployedgenerally about he annulus, the ventricle and the ascending aorta.Deployment of the anchoring hooks may be enhanced by radial expansion ofa balloon catheter that further engages the hooks into the surroundingstructures. Blood pump 674 is stopped and blood pump catheter 676 isremoved. Other configurations may be adapted for replacing a valve atother site will be familiar to those skilled in the art.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrative,and not restrictive and the scope of the invention is, therefore,indicated by the appended claims rather than by the foregoingdescription. For all of the embodiments described above, the steps ofthe methods need not be performed sequentially. All changes that comewithin the meaning and range of equivalency of the claims are to beembraced within their scope.

What is claimed is:
 1. A prosthetic cardiac valve assembly comprising:a) a replacement valve comprising: a plurality of leaflets configured topermit blood to selectively flow therethrough; and a plurality ofcommissure points from which the replacement valve is suspended; b) avalve support connected to the replacement valve and configured to becollapsible for trans luminal delivery, said valve support having anaxial length sufficient to extend, when implanted, from a position of anative annulus, past the replacement valve, past the commissure points,and past the patient's coronary ostia, and into an ascending aorta;wherein outer circumference of the valve support varies along at leastsome portions of the axial length; wherein the valve support furthercomprises: a first section terminating in a first end, said first endcomprising an outer circumference having a first diameter, said firstsection configured to engage the native annulus; and a second sectionterminating in a second end, said second end comprising an outercircumference having a second diameter, said second section configuredto extend past the coronary ostia and into the ascending aorta, whereinthe second circumference is greater than the first circumference.
 2. Theprosthetic cardiac valve assembly of claim 1, wherein said first sectioncomprises a plurality of intersecting members forming a plurality ofcells, said cells having a first cross-sectional size and arrangedsubstantially uniformly around a periphery of the valve support; whereinthe second section comprises a plurality of intersecting members forminga plurality of cells, said cells having a second cross-sectional sizeand arranged substantially uniformly around a periphery of the valvesupport; and wherein the second cross-sectional size is greater than thefirst cross-sectional size.
 3. The prosthetic cardiac valve assembly ofclaim 2, wherein the cells at the first and second sections comprise adiamond shape.
 4. The prosthetic cardiac valve assembly of claim 1,wherein the valve support is self-expanding.
 5. The prosthetic cardiacvalve assembly of claim 1, wherein the valve support comprises aplurality of wires.
 6. The prosthetic cardiac valve assembly of claim 1,wherein the valve support comprises a shape memory material.
 7. Theprosthetic cardiac valve assembly of claim 6, wherein the shape memorymaterial comprises Nitinol.
 8. The prosthetic cardiac valve assembly ofclaim 1, wherein the replacement valve is secured to the valve supportusing at least one suture.
 9. The prosthetic cardiac valve assembly ofclaim 1, wherein the replacement valve comprises at least threeleaflets.
 10. The prosthetic cardiac valve assembly of claim 1, whereinat least a portion of the valve support is configured to apply a radialexpansion force up to a predetermined diameter.
 11. A prosthetic cardiacvalve assembly comprising: a replacement valve comprising a plurality ofleaflets and a plurality of commissure points from which the replacementvalve is generally suspended; and a valve support having a proximalportion and a distal portion, said valve support connected to thereplacement valve and configured to be collapsible for trans luminaldelivery; wherein the valve support is configured to extend, whenimplanted into a patient, from a native annulus at the proximal portionto an ascending aorta at the distal portion, past a location of thepatient's coronary ostia; wherein an outer shape of the valve supportvaries along an axial length of said valve support such that across-sectional dimension of the distal portion is generally larger thana cross-sectional dimension of the proximal portion; wherein the valvesupport comprises a plurality of intersecting members forming aplurality of cells, said cells being arranged substantially uniformlyaround a periphery of the valve support; and wherein the plurality ofcells located along the distal portion of the valve support have alarger cross-sectional size than the plurality of cells located alongthe proximal portion of the valve support.
 12. The prosthetic cardiacvalve assembly of claim 11, wherein the valve support comprises aproximal end and a distal end, a cross-sectional dimension of saiddistal end being larger than a cross-sectional dimension of saidproximal end.
 13. The prosthetic cardiac valve assembly of claim 11,wherein the plurality of cells at the proximal and distal portionscomprise a diamond shape.
 14. The prosthetic cardiac valve assembly ofclaim 11, wherein the valve support is self-expanding.
 15. Theprosthetic cardiac valve assembly of claim 11, wherein the valve supportcomprises a plurality of wires.
 16. The prosthetic cardiac valveassembly of claim 11, wherein the valve support comprises a shape memorymaterial.
 17. The prosthetic cardiac valve assembly of claim 16, whereinthe shape memory material comprises Nitinol.
 18. The prosthetic cardiacvalve assembly of claim 11, wherein the replacement valve is secured tothe valve support using at least one suture.
 19. The prosthetic cardiacvalve assembly of claim 11, wherein the replacement valve comprises atleast three leaflets.
 20. The prosthetic cardiac valve assembly of claim11, wherein at least a portion of the valve support is configured toapply a radial expansion force up to a predetermined diameter.
 21. Aprosthetic cardiac valve comprising: a) a replacement valve comprising:a plurality of leaflets configured to permit blood to selectively flowtherethrough; and a plurality of commissure points from which thereplacement valve is suspended; and b) a valve support connected to thereplacement valve and configured to be collapsible for transluminaldelivery, wherein, when the valve support is implanted in a patient andthe replacement valve is positioned in a native aortic valve annulus,said valve support is sized and shaped to extend from a position of thenative annulus, past the replacement valve, the commissure points, andthe patient's coronary ostia, and into an ascending aorta; wherein outercircumference of the valve support varies along at least some portionsof the axial length; wherein the valve support further comprises: afirst section terminating in a first end, said first end comprising anouter circumference having a first diameter, said first sectionconfigured to engage the native annulus; and a second sectionterminating in a second end, said second end comprising an outercircumference having a second diameter, said second section configuredto extend past the coronary ostia and into the ascending aorta, whereinthe second circumference is greater than the first circumference.